C) Inside hexagonal screw: Inside hexagonal screw is suitable for small installation space or screw head need to be embedded occasions, see GB70, GB6190-6191 and GB2672-2674, etc.
D) Special purpose screw: such as positioning screw, non-removal screw and ring screw, see GB72, GB828-829, GB837-839, GB948-949 and GB825, etc.
(a) Unequal-length double-headed studs: suitable for the occasion where one end is screwed into the part body for connecting or fastening, see GB897-900;
B) Equal length double-headed stud: suitable for connecting or fixing distance between two ends and nuts. See GB901, GB953, etc.
It is divided into many varieties according to the head type and groove shape. Head type has round head, countersunk head, semi-countersunk head and so on. Head groove is grooved (one-word groove) and cross groove, see GB99-101, GB950-952.
(a) General self-tapping screw: thread conforms to GB5280, pitch is large, suitable for use in thin steel plate or copper, aluminum, plastic, see GB845-847, GB5282-5284, etc.
B) Self-tapping locking screw: The thread conforms to the common meter thick tooth thread, suitable for use in vibration-resistant occasions, see GB6560-6564.
A) Flat gasket: for overcoming unevenness of workpiece support surface and increasing stress area of support surface, see GB848, GB95-97 and GB5287;
B) Spring (elastic) washer: Spring washer relies on elasticity and oblique friction to prevent fasteners from loosening, and is widely used in frequently disassembled connections. There are many sharp elastic warping teeth on the circumference of inner teeth elastic washer and outer teeth elastic washer, which can be stabbed on the supporting surface to prevent the loosening of fasteners. The inner tooth elastic washer is used under the smaller head size of the screw head, while the outer tooth elastic washer is mostly used under the bolt head and nut. The elastic washer with teeth is smaller than the ordinary spring washer. The fastener is uniform in force and reliable in preventing loosening, but it is not suitable for common disassembly. See GB93, GB859-860 and GB955;
C) Back stop washer: there are internal locking washer, external locking washer, single ear stop washer, double ear stop washer and round nut stop washer, etc. Single-ear and double-ear stop washers allow nuts to be tightened to lock at any position, but the fasteners should be located near the edge, see GB861-862, GB854-855, GB858, etc.
D) Oblique washer: In order to adapt to the slope of the working support surface, oblique washer can be used. Square diagonal washer is used to flatten inclined surfaces such as channel steel and I-shaped steel flange, so that the nut support surface is perpendicular to the screw rod, so as to avoid bending force on the screw rod when the nut is tightened. See GB852-853, etc.
(a) Elastic retaining rings: elastic retaining rings for axles and holes are clamped in axle grooves or hole grooves for rolling bearings to stop retreating after loading. In addition, there are open retaining rings for axles, which are mainly used for fixing parts in axle grooves, but can not bear axial force. See GB893-894 and GB896;
B) Steel wire retaining ring: steel wire retaining ring and steel lock ring with holes (for axles). The steel wire retaining ring can also bear certain axial force when it is installed in the shaft groove or hole groove for parts positioning. See GB895.1 to.2, GB921;
(c) Locking ring for axle parts: a retaining ring with taper pin and a retaining ring with screw, mainly used to prevent axle parts from moving axially. See GB883-892.
D) Axis end retaining ring: Axis end retaining ring fastened with screw and axle end retaining ring fastened with bolt are mainly used to lock parts fixed at axle end. See GB883-982.
A) Cylindrical pins: Cylindrical pins are mostly used for fixing parts on axles, transferring power, or as positioning elements. Cylindrical pins have different diameter tolerances, which can be used for different matching requirements. Cylindrical pin is usually fixed in the hole by interference, so it is not suitable to disassemble more. See GB119-120, GB878-880, etc.
B tapered pin: tapered pin with a taper of 1:50, easy to install eye-to-eye, but also to ensure self-locking, generally used as positioning elements and connecting elements, mostly used in places requiring frequent disassembly. Internal thread taper pins and tail taper pins are used in non-perforated holes or in holes where pins are difficult to punch out. The rear end of the opening taper pin penetrating the hole can be opened to prevent the pin itself from sliding out of the hole. See GB117-118, GB881 and GB877, etc.
The pin holes of cylindrical pins and conical pins are usually machined by reaming. After many times of assembly and disassembly, the positioning accuracy and connection tightness will be reduced, and only a small load can be transmitted. The elastic cylindrical pin itself has elasticity. It keeps tension in the hole, is not easy to loosen, is easy to disassemble, and does not affect the matching property. The pin hole does not need to be articulated. Holed pins and pins are used at hinge joints.
C) Open pin: Open pin is an anti-loosening device for connecting parts. When used, it penetrates into pin holes of nuts, bolts with pin holes or other connecting parts, and then separates the feet. See GB91.
(a) Hot forging rivets: generally large specifications, mostly used in locomotives, ships and boilers, usually need to be hot forged to make the head shape, see GB863-866;
B) Cold heading forming rivet: General diameter specification 16 mm, usually through cold heading to make the head shape, see GB867-870, GB109, etc.
(c) Hollow and semi-hollow rivets: Hollow rivets are used to connect plastic, leather, wood, canvas and other non-metallic parts where the shear force is not large.